Category Archives: Safety

Dispose of Your Biosludge with this New & Improved System

Getting rid of secondary sludge, or biosludge, has always been an industry issue bringing forward many problems due to its high water content and the nature of the solids contained. With these drawbacks, transportation and disposal become problematic.

As of recent, field experts are focused on improving what we currently know as traditional disposal methods like landfilling or incineration in the power boiler.

Drawbacks to the traditional approaches include:

  • Offensive odor
  • Water leaching from landfill sites
  • Low thermal efficiency
  • Potential health hazards in handling
  • Overall cost of disposal

With landfills for biomass material now banned in Europe, a new approach was needed and for several mills, this was to incinerate the biosludge in the recovery boiler.

Through a proprietary system, the biosludge is hydrolyzed by mixing it with black liquor and then sent off to the concentrator for disposal in the recovery boiler.

New benefits of this approach include:

  • No offensive odor
  • No handling or transfer of the sludge for transport
  • Higher thermal efficiency by using the multiple effect economy of the evaporators
  • Incineration occurs within the recovery boiler with no real change in operation
  • Lower cost solution internal to the mill operations

Current studies reveal that no significant negative impacts have been experienced in the mills that have taken on incineration of secondary sludge within the recovery boiler.

For more of an in-depth look at the recovery boiler system read our recent white paper. The analysis includes an overview of the secondary sludge hydrolysis process, detailed benefits of hydrolyzing and disposing of sludge in the recovery boiler, user experience, and additional links and information on Valmet Automation products for wastewater handling.

Valmet has over 40 years of experience in the boiler system industry. Our skilled team of industry experts can help improve your handling and disposal of secondary sludge needs.

For more information on biosludge disposal methods and recovery boilers remember to stay up to date with our latest blogs, find us on Facebook, follow us on Twitter, and connect with us on LinkedIn.

For immediate inquiries please contact us today.

Improving Safety Around Recovery Boiler Operations

The recovery boiler is a vital part of the pulp mill but also a source of potential safety hazards for its operators. One of the purposes of the recovery boiler is to recover the pulping chemicals from the black liquor which is done in the form of smelt from the bottom of the furnace. A potential hazard of this process is that if the smelt interacts or has contact with water, an explosion can potentially occur which could injure operators and cause damage to the boiler. Besides the risk of explosion, combustion in the recovery boiler creates very hot gases and highly corrosive molten ash which could be hazardous to operators who are performing physical tasks around the recovery boiler.

In an effort to make operations in the recovery boiler safer, and minimize exposure to unsafe working conditions, Valmet has developed and perfected several auxiliary devices that serve to both automate as well as either remove the need for direct operator involvement or to minimize exposure to unsafe working conditions. Below are four inventions and innovations that have improved the working conditions around recovery boilers and made operation of the boiler more stable.

Smelt Spout Micro Hood Arrangement: One area considered the most dangerous for operators, and one of the leading causes of recordable injuries is the spout deck on a recovery boiler. To make smelts more accessible for cleaning and to improve safety, Valmet has developed mini or micro-hoods have to replace the old large hood systems. The benefits of these systems are:

• Easier access to spouts for manual cleaningSmelt Spout Micro Hood Arrangement
• Easier replacement of spouts
• Minimal hood shower water
• Minimal internal ledges
• Cooling water lines not exposed to smelt
• Minimizes tramp air intake
• Dual shatter jets (ShatterMax™)
• Externally mounted shower bar headers
• More reliable mounting interfaces for the smelt spouts.

Spout Cleaning Robot: The DeckHand™ is another new system designed to improve the safety of operators is the development of an independent robotic arm that performs repetitive tasks. The safety benefits of this robot are:

Spout Cleaning Robot

• Greatly reduces the risk of operators getting injured from splashes of green liquor or smelt
• Cleans spouts, hoods & shatter jets
• Robot camera that allows operators to visually inspect spouts from safe control room
• Safety gates designed to stop robot if any personnel enters the spout deck
• Less personnel at the smelt spouts

Liquor Station with Automated Port Rodder: Working around the liquor guns is another area where operators are at risk with large numbers of lifting and burn injuries being reported annually. To make this area safer, the GunnersMate™ liquor stations were developed. The safety benefits are:

Liquor Station with Automated Port Rodder

• Limited operator exposure to furnace
• Station retractable outside furnace
• Safety door protection from opening
• Ready signal for spraying to start
• Improved operator working conditions
• Auto-cleaning cutter reduces amount of manual cleaning required

Automated Port Rodders: The Roddingmaster™ was developed to limit operators from potential exposure to hot air (300 – 400 °F) and limit exposure to the furnace. The safety benefits of automated port rodders are:

Automated Port Rodders

• Improved operator working conditions
• Large observation port
• Control box easy access for remote isolation
• Ability to change the cutter on the run with minimum exposure time in front of opening


At Valmet we can help you with all your recovery boiler safety needs. Contact us for more information.